1. Field of the Invention
Most doors open and close on freely-swinging hinges. This invention is in the field of devices associated with the hinge or integral with it which enable the free swinging to be positively stopped, so the door will not swing. Normally it would be used to lock the door shut. The security hinge may be used alone or in conjunction with a lock on the handle side of the door. If the latter, both sides of the door are locked independently of each other.
2. Description of Prior Art
Most hinges do not lock. However, the advantages of having a hinge capable of being locked are such that prior art on the subject exists. These range from Walters (U.S. Pat. No. 3,711,894) who essentially builds a miniature lock into the hinge pin, the bolt of which pins together the annular portions surrounding the hinge pin (here called knuckles) to McCullough (U.S. Pat. No. 3,874,029) and Griego (U.S. Pat. No. 3,744,085) both of which slide the hinge pin axially to accomplish the locking action. Since the hinge pin is supporting the door, the need to slide it is a serious drawback to these devices as a considerable force may be required to move the locking parts into full engagement. This would be particularly true after wear had occurred or after some corrosion or foreign matter had been deposited within the mechanism. A further drawback to both the latter devices is the difficulty of assembly, making it necessary for the carpenter mounting the door either to mount the hinge without disassembling it, or to learn its proper assembly. McCullough's lock relies on a transverse pin through the hinge pin for its holding power. Thus the lock could be overpowered or broken once the knob side of the door had been opened.
As is pointed out in the following, these limitations and disadvantages of the prior art are avoided by our invention.